Celtics' Marcus Smart will miss 2 weeks because he punched a picture frame

Marcus Smart is expected to miss two weeks with a right hand laceration. (AP)

Two days after Boston Celtics coach Brad Stevens broke the news that Marcus Smart required stitches for a mysterious laceration to his right hand, the fourth-year guard finally explained how it happened.

Smart punched a picture frame on the wall of the team hotel in Los Angeles at some point between Boston’s games against the Lakers and Clippers at Staples Center on Tuesday and Wednesday night.

I want to take this time to express my sincerest apologies to my teammates, coaches, and most of all the amazing Boston Celtics fans. I'm embarrassed and disappointed in my actions. I swiped at and hit a picture frame on the wall. I feel like I let all y'all down

While the Celtics continue their West Coast road trip against the reigning champion Golden State Warriors on Saturday night, Smart returned to Boston to undergo a medical evaluation. He is expected to miss approximately two weeks, the team announced on Friday afternoon. Smart’s defense has been a key component of Boston’s success against the Warriors backcourt over the past three seasons.

Smart missed a contested 3-point shot in transition in the final seconds of the Celtics’ 108-107 loss to the rival Lakers on Tuesday — the team’s fourth straight defeat. He came under criticism after replays revealed backcourt mate Terry Rozier was open on the wing for what appeared to be a better look.

The Celtics only announced that Smart’s injury occurred “prior to Wednesday night’s game” against the Clippers. Without Smart and center Al Horford, who missed the game with concussion-like symptoms, Boston snapped a season-high four-game losing streak with a 113-102 win over the Clips.

Smart’s two-week timeline could also cost him key games against the Toronto Raptors and Washington Wizards on Feb. 6 and 8, respectively. The Celtics lead the Raptors by 1.5 games for first place in the East, and the Wizards took them to seven games in the conference semifinals last season.

Smart is averaging 10.1 points (on just 35.7 percent shooting), 4.7 assists and 3.6 rebounds in 30.2 minutes per game off the bench, but he’s an All-Defensive-caliber player whose impact on Boston’s success goes beyond traditional statistics. He will be a restricted free agent at season’s end.